The 5500-series mills are essentially a Model 5000-series mill upgraded to include adjustable “zero” handwheels in place of the standard non-resettable handwheels. They feature the same solid 10" (254mm) aluminum base, precision machined dovetailed slides with adjustable gibs, permanently lubricated spindle bearings, adjustable preload anti-backlash feed screws on the X- and Y-axes, and many other features found only on the best commercial machines.